This has been discussed to death. It is not planned, and not (readily) feasable.
just out of curiosity, why wouldn't this be feasible?
one of the ftp clients that i used to prefer is WSftp
it does support sftp now as well, but it is a much larger footprint on memory, and a much bulkier program (and it no longer has a free version)
there use to be WSftp Pro and WSftp Lite (free). they have now continued WSftp Pro, but replaced the Lite version with WSftp Home, which is $39.95 (US Dollars).
i am not sure on the home version, but the Pro version supports sftp transfers, but you can have two remote windows, two local windows, or one of each